RESOURCES

Electrical Apparatus Service Association (EASA) www.easa.com This international trade organization has nearly 2,400 electromechanical sales and service firms in 56 countries.

em2solutions www.em2solutions.com is a private company who makes electric motor management software solutions, Websites and electric motor seminars available to motor consumers, motor service centers and utilities nationwide.

Hydraulic Institute http://www.pumps.org is a trade association of the pump industry.

Motor Decisions Matter www.motorsmatter.org is a national campaign encouraging the use of sound motor management and planning as a tool to cut industry's energy costs and increase productivity. The campaign is sponsored by a consortium of motor manufacturers, EASA International, trade associations, electric utilities, and government agencies.

NEMA Premium™ www.nema.org/index_nema.cfm/1018 The member companies of the NEMA Motor and Generator Section established a NEMA Premium™ energy efficiency motors program to provide highly energy efficient products that meet the needs and applications of users and original equipment manufacturers based on a consensus definition of "premium efficiency".

Northwest Energy Efficiency Alliance www.nwalliance.org is a non-profit corporation supported by electric utilities, public benefits administrators, state governments, public interest groups and energy efficiency industry representatives. These entities work together to make affordable, energy-efficient products and services available in the Northwest marketplace.

TAPPI www.tappi.org is a trade association of the pulp and paper industry.

U.S. Department of Energy Best Practices www.oit.doe.gov/bestpractices/motors supports improved industrial motor management practices as a part of the Office of Industrial Technologies. Best Practices provides resources - publications, and information - that's specific to motor systems.

Q. How different is a full load analysis from a true load analysis?

A. "True load" is based on torque delivered to the output shaft and is best measured with a kW meter and a dynamometer. Amperage/voltage readings should never be considered "true load" but are satisfactory when comparing motors or determining if a motor is operating at full load. Keep in mind the nearer to 100% load the more accurate amperage/voltage reading will be.

Q.If a motor has no nameplate can it be rewound or replaced?

A. There are a lot of questions to be answered but yes our skilled service center staff can (98% probable) determine a suitable replacement. In regard to rewinding the motor, we would cross reference the motor with EASA's rewinding database to even more certainly identify the motor. This is a classic example of why a digital or hardcopy database of a companies operating and spare motors should be kept up to date.

Q. How do I determine whether my motor is running at full or part load?

A. Measuring amperage and comparing it with the full load or nameplate value is a simple way to get an idea. However, keep in mind that the accuracy will deteriorate the further the deviation from 100% load. This information should be acceptable when comparing motors to determine if it is better to repair or replace based on cost of operation.

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Q. Do hours of operation affect my electricity use?

A. WOW, does it! Very little change in hours of operation will make big differences in energy consumption.

Q. Why do NEMA Premium™ motors tend to run hotter and not last as long as standard motors that they replace?

A. A motor meeting “NEMA Premium” standards should run cooler, quieter and last longer. A consideration many times overlooked when replacing an existing motor, is that more efficient motors tend to be higher performing and may run a little faster. If the motor your replacing is running less than fully loaded and your process can utilize the new faster motor you’ll probably get the results and energy savings expected. However, motors applied to pumps, fans and blowers or variable torque loads, are many times affected by speed more profoundly than constant torque loads. For example: On a closed impeller centrifugal water pump, by replacing a 10 Hp, 1725 RPM with a motor at 1760 RPM you may now need 10.6 Hp. By making this change and disregarding the higher speed the motor may run hotter, use more energy and not last as long. Electric Motor Service Company may be able to help you by trimming the impeller or supplying appropriate sheaves and recommending other changes that will provide the results expected.

Q. Do I need to replace an existing motor when I install a variable speed drive?

A. No, not necessarily. The existing motor will probably operate satisfactorily for some time without change. However, there are other considerations like warranty and reliability that may cause the replacement when the VFD is installed. As a rule of thumb the smaller the motor the less tolerant to PWM drives. Adding a load reactor, NEMA Premium™ motor or a motor wound with spike resistant wire tend to be more tolerant.

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Q. Does a motor loose efficiency with each rewind it endures?

A. Rewinding is a very intrusive procedure involving the removal and replacement of the motors entire electrical system. In this process our company makes every effort to improve a manufacture's original choices in wire, slot fill and/or winding style so that the motor retains or is even slightly more efficient. On the other hand the failure event could have a negative impact on motor performance that is irreparable effecting efficiency and reliability.

Q. Can lubrication by our maintenance staff impact electric motor efficiency and reliability?

A. Yes, over lubrication and incompatible greases cause all kinds of problems. In a recent study, greasing a motor caused a decrease in motor efficiency by 1%. What can happen is that the added pressure may collapse the bearing shield or seal causing additional drag resulting in an efficiency and reliability loss. Many manufactures have recently changed grease types so reviewing current manufactures recommendations and lubrication compatibility might be a good idea. Contact us if you'd like some help with lubrication types.

Q. Why should our company request any service center follow written repair purchasing specifications and what documentation should we require to be assured of a "best practice" rewind?

A. Having a document outlining your companies needs and wants from our company or any service center eliminates speculation for both of us and provides some consistent targets. But documentation won't eliminate the responsibilities in obtaining a level of "best practice" procedures for each individual motor. It's only a start; we share the responsibility and must be particular but flexible to make each job is a "best practice" procedure. Upon request we will provide core loss, vibration, surge comparison, megger, resistance and no load volt/current test results. This data should be stored in your companies motor database for future reference. When the motor is sent to us or another service center it should be accompanied with complete nameplate data, location environment; operating volt/amp readings and past repair history.

Q. What documentation should be exchanged between a motor service center and the service purchaser?

A. When a motor is sent in to the service center it should be accompanied with complete nameplate data, operating voltage and amperage readings, application details, environment and service history. Upon completion the service center should provide no load test, balance and core loss test results along with root cause failure analysis, bearing part numbers, lubrication type and quantity along with interval recommendations

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